Geographic Range

Guianan white-eared opossums (Didelphis imperfecta) are found in northern to central South America. This species is endemic to Guyana, Suriname, French Guiana, Venezuela and Brazil, however, they are likely also found in western Ecuador and northeastern Peru. (Cerqueira and Tribe, 2008; Lew, et al., 2011)

Habitat

Guianan white-eared opossums are found at a variety of elevations. They may inhabit lowland rainforests at elevations as low as 60 m, or elfin forests on tepuis, or mesas, as high as 2,550 m. This species is known to inhabit the Venezuelan mountain, Cerro Marahuaca. (Cerqueira and Tribe, 2008; Lew, et al., 2011)

There have been very few published accounts detailing the physical appearance of Guianan white-eared opossums. However, given that this species was grouped with Didelphis albiventris until very recently, it is likely that these species share many similarities. These opossums are relatively robust. The fur on their faces has a dusty-whitish hue, with a dark gray medial stripe. Guianan white-eared opossums typically have whitish ears and a pointed muzzle. Their prehensile tails are largely hairless and scaly, with the exception of fur at the base of the tail and a bit of sparse fur throughout. These species have a pronounced sagittal crest and the following dental formula: 5/4, 1/1, 3/3, 4/4. Females have a marsupium with 13 mammae. (Cerqueira and Tribe, 2008; Lemos and Cerqueira, 2002; Oliveira and Santori, 1999; Smith, 2007; de Almeida, et al., 2008)

Reproduction

There is no specific information regarding the mating systems of Guianan white-eared opossums. However, members of family Didelphidae are generally considered polygynous. Males compete for reproductive females, communicating with a series of clicking noises. Didelphids show neither courtship displays nor pair bonds. (Fernandes, et al., 2010; O'Connell, 2006)

There is little published information specifically regarding the reproductive behavior of Guianan white-eared opossums. However, there appears to be little behavioral variation in the studied members of their genus. These species typically have 2 breeding periods; breeding generally begins at the end of the dry season and offspring are born during the wet season. The gestation period for these species tends to be very short, about 12 to 14 days on average. The specific number of young produced by Guianan white-eared opossums is not known, however, their close relative Didelphis albiventris typically has 4 to 23 young. These offspring are extremely altricial; they are often about 15 mm long and weigh about 0.13 grams. (O'Connell, 2006; Rademaker and Cerqueira, 2006; Smith, 2007; Talamondi and Dias, 1999)

The parental investment of Guianan white-eared opossums has not been reported, however, research has been conducted on their close relative, white-eared opossums (Didelphis albiventris). Once the offspring of white-eared opossums are born, they must climb to the marsupium. Although a female may have many offspring within a litter, their marsupium only includes 13 mammae, as such, many of these altricial young will not survive. Young white-eared opossums remain within the pouch attached to the mammae for the first two months of their life, after which, they cling to their mothers back. They will stay with their mother for several more weeks; they are weaned at 3 to 4 months of age. White-eared opossums are sexually mature at around 9 months. (Cerqueira and Tribe, 2008; Rademaker and Cerqueira, 2006; Smith, 2007)

Lifespan/Longevity

The lifespan of Guianan white-eared opossums has not been reported, however, most didelphids have a very short lifespan. For instance, white-eared opossums typically do not survive beyond 20 months of age. (Smith, 2007)

Behavior

Guianan white-eared opossums are solitary marsupials, although they may feed in similar areas with conspecifics, they do not interact. They are primarily terrestrial, but they are also adept climbers. These animals are nocturnal. During daylight hours Guianan white-eared opossums take shelter in abandoned termite nests, hallow trees or in the tree canopy, likewise, they may build leaf nests or burrow for refuge. (Lew, et al., 2011; O'Connell, 2006; Rademaker and Cerqueira, 2006)

Home Range

The home range size of Guianan white-eared opossums has not been reported.

Communication and Perception

The perception channels of Guianan white-eared opossums have not been reported, however, research has been conducted on other members of genus Didelphis. White-eared opossums primarily detect food items using their olfactory and auditory senses. In general, members of genus Didelphis also have very good eyesight. Likewise, members of this genus are equipped with long whiskers, which help them navigate at night. When these animals perceive a threat they typically bare their teeth, they can also run rather quickly when they are on the ground, their speed is impaired when they are climbing. In somewhat rare cases, when white-eared or Virginia opossums perceive an extreme threat, they may feign death. (O'Connell, 2006; Oliveira and Santori, 1999; Smith, 2007)

Economic Importance for Humans: Positive

There are no known positive impacts of Guianan white-eared opossums on human populations.

Economic Importance for Humans: Negative

There are no known negative impacts of Guianan white-eared opossums on human populations.

Conservation Status

Guianan white-eared opossums are currently listed as a species of least concern according to the IUCN Red List of Threatened Species. These animals are believed to have a sizable and steady population. (Lew, et al., 2011)

Contributors

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

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The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.